This section is intended to provide a background or context to the invention disclosed below. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise explicitly indicated herein, what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:                C-SON Centralized Self Optimizing Network        DL DownLink (from base station to user equipment)        eNB or eNode B evolved Node B (LTE base station)        ES Energy Savings        HO HandOver        IE Information Element        L1 a physical layer (e.g., PHY)        L2 a data link layer (e.g., RLC/MAC)        L3 a network layer (e.g., RRC/RRM)        LTE Long Term Evolution        MAC Media Access Control        MDT Minimization Drive Testing        MME Mobility Management Entity        O&M Operations and Maintenance        PA Power Amplifier        PDCP Packet Data Convergence Protocol        RAN Radio Access Network        Rel Release        Rx or RX receiving or receiver        RLC Radio Link Control        RRC Radio Resource Control        RRM Radio Resource Management        SGW Serving GateWay        SON Self Optimizing Network        Tx or TX transmitting or transmitter        UE User Equipment        Uu LTE air interface        XCVR transceiver        
An Energy Savings (ES) method via deactivating unneeded eNB cell(s) has been a supported functionality in LTE since Rel-9. 3GPP TS 36.423 V11.0.0 (2012-03), section 8.3.11 (Cell Activation) provides details for the X2 application protocol (X2AP) including the Cell Activation procedure used to request to a neighboring eNB to switch on one or more cells, previously reported as inactive due to energy saving reasons. 3GPP TS 36.300 V11.0.0 (2011-12), provides the Overall E-UTRA and E-UTRAN description where section 22.4.4.2 (“Solution description”), currently contains the following text regarding support for Energy Savings:
“All informed eNBs maintain the cell configuration data also when a certain cell is dormant. ENBs owning non-capacity boosting cells may request a re-activation over the X2 interface if capacity needs in such cells demand to do so. This is achieved via the Cell Activation procedure.”
Thus, cell re-activation occurs when “capacity needs demand to do so”. It can also be seen that cells may enter an inactive or an active state. While this may increase energy saving as compared to having all cells active, additional improvements are also possible.